This invention relates to an apparatus or machine for applying adhesive to a predetermined area on a surface of an article. More particularly, the invention relates to an apparatus or machine for use in the production of packages in large quantities in which there is a requirement for applying or depositing adhesive on a predetermined area of a succession of package-forming components with the deposited adhesive being subsequently relied on to form an hermetic seal.
In recent years one type of package that has achieved a high degree of commercial success has comprised a relatively stiff or semi-rigid backing member or base component on which a product to be packaged is located and over which is secured a transparent cover which may be in the form of either a preformed transparent plastic bubble or a transparent film. This type of package has been widely used in the food industry for packaging sliced luncheon meats and cheese. One such package and method and apparatus for forming the same is disclosed in U.S. Pat. No. 3,498,018 to Oscar F. Seiferth et al.; U.S. Pat. No. 3,349,540 dated Oct. 31, 1967 to Hans A. Jensen et al.; and U.S. Pat. No. 3,478,488 dated Nov. 18, 1969 to Hans A. Jensen et al. Similar packages are also widely used for display-packaging of a wide variety of non-food articles in so-called "blister" packages.
In forming packages of the foregoing type, various systems have been used for applying or depositing adhesive to the seal areas of the stiff or semi-rigid backing components, although the adhesive has also or alternatively been applied to the transparent bubble or blister component. One such system and apparatus is disclosed in the above-mentioned U.S. Pat. No. 3,349,540 wherein transfer rollers remove adhesive from a supply fountain and transfer the adhesive onto applicator rollers which in turn deposit the adhesive on the desired seal area on a semi-rigid plastic support or base used in forming a sliced food package.
The previous commercially used apparatus and methods of applying adhesive to the seal areas of package components have had several recognized draw-backs. In particular, the adhesives had to be applied in relatively viscous and heated condition which severely limited the types and properties of adhesives that could be used and tended to excessive consumption of adhesive.
In the apparatus and method of the present invention an adhesive pick-up and applicator element in the form of a sleeve has a lip at the top with a shape and area corresponding to the seal area on which it is desired to apply or deposit adhesive to a series of package components. Such an adhesive pick-up and applicator element is reciprocated between a lowered position in which the lip is immersed in a pool or bath of adhesive and an upper position in which the lip is raised above the surface of the adhesive and engages the seal area of an article to which the adhesive is to be applied or deposited. Depending upon production volume requirements, the apparatus of the present invention may consist of and be operated as a single unit or comprise a gang of units operating in unison.
The object of the invention, generally stated, is the provision of an improved apparatus and method for applying adhesive to package components and other articles in which the lip of an adhesive pick-up and applicator element is reciprocated so as alternately to be immersed below the surface of a body of adhesive and then raised above the surface into engagement with the seal area of the package component or other article having a seal area requiring the application of adhesive.
A number of other important and more specific objects of the invention will be apparent to those skilled in the prior art in view of the following Detailed Description of Preferred Embodiments of the Invention taken in conjunction with the accompanying drawings, wherein: